How to draw a circle in HTML5 Canvas using JavaScript?

Here is how to draw a circle using JavaScript in HTML5:

const canvas = document.getElementById('myCanvas');
const context = canvas.getContext('2d');
const centerX = canvas.width / 2;
const centerY = canvas.height / 2;
const radius = 70;

context.beginPath();
context.arc(centerX, centerY, radius, 0, 2 * Math.PI, false);
context.fillStyle = 'green';
context.fill();
context.lineWidth = 5;
context.strokeStyle = '#003300';
context.stroke();

body {
  margin: 0px;
  padding: 0px;
}

<canvas id="myCanvas" width="578" height="200"></canvas>

I took the answers above and turned them into a useful function:

function drawCircle(ctx, x, y, radius, fill, stroke, strokeWidth) {
  ctx.beginPath()
  ctx.arc(x, y, radius, 0, 2 * Math.PI, false)
  if (fill) {
    ctx.fillStyle = fill
    ctx.fill()
  }
  if (stroke) {
    ctx.lineWidth = strokeWidth
    ctx.strokeStyle = stroke
    ctx.stroke()
  }
}

Then, use it like so to draw a black circle with a red stroke (width 2) at coordinates 50,50, with radius 25:

let ctx = canvas.getContext('2d')
drawCircle(ctx, 50, 50, 25, 'black', 'red', 2)

Creating shapes is easier using new Canvas Path2D, which uses the same canvas drawing API, and allow separation of the declaration from drawing itself, and reuse of complex geometry:

var canvas = document.getElementById('myCanvas');
var context = canvas.getContext('2d');
var centerX = canvas.width / 2;
var centerY = canvas.height / 2;
var radius = 70;

let circle = new Path2D();  // <<< Declaration
circle.arc(centerX, centerY, radius, 0, 2 * Math.PI, false);

context.fillStyle = 'blue';
context.fill(circle); //   <<< pass circle to context

context.lineWidth = 10;
context.strokeStyle = '#000066';
context.stroke(circle);  // <<< pass circle here too

body {
margin: 0px;
padding: 0px;
}

<canvas id="myCanvas" width="578" height="200"></canvas>

How to draw a circle in HTML5 Canvas using JavaScript?

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